首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   91篇
  免费   1篇
电工技术   2篇
化学工业   18篇
机械仪表   1篇
建筑科学   1篇
轻工业   8篇
无线电   6篇
一般工业技术   4篇
冶金工业   29篇
自动化技术   23篇
  2024年   2篇
  2023年   1篇
  2022年   2篇
  2021年   4篇
  2020年   1篇
  2018年   1篇
  2017年   1篇
  2016年   4篇
  2014年   1篇
  2012年   2篇
  2011年   3篇
  2010年   3篇
  2009年   4篇
  2008年   4篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2003年   2篇
  1998年   13篇
  1997年   6篇
  1996年   4篇
  1995年   5篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1985年   3篇
  1983年   2篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有92条查询结果,搜索用时 0 毫秒
71.
Iwama H 《Indoor air》2004,14(4):293-297
To elucidate a potential mechanism by which negative air ions improve aerobic metabolism, changes in venous blood lactate levels, pH, erythrocyte deformability, and plasma superoxide dismutase activity and ceruloplasmin levels were examined during a 1-h exposure to negative air ions created by water shearing or corona discharge in nine adult healthy volunteers. The blood lactate level decreased from 1.3 +/- 0.3 to 1.0 +/- 0.2 mmol/l, pH increased from 7.388 +/- 0.025 to 7.417 +/- 0.036, and erythrocyte deformability improved from 37.0 +/- 2.2 to 35.1 +/- 3.0 s, expressed as the mean +/- s.d., when exposed to negative air ions created by water shearing, but did not change when exposed to negative air ions created by corona discharge. Other variables did not change in either exposure. The results obtained suggest that negative air ions created by water shearing improve aerobic metabolism by improving erythrocyte deformability. PRACTICAL IMPLICATIONS: The paper shows that negative air ions created by water shearing method improve aerobic metabolism only during a 1-h exposure, which may be caused by improvement of erythrocyte deformability, but negative air ions created by corona discharge have no effects. A potential mechanism is that negative air ions enter the circulating blood via the lungs and electrons of these ions are delivered to the plasma protein. Why negative air ions created by corona discharge have no effects is considered that water binding does not exist so that the lifetime of these ions is markedly short, by which the ions cannot reach the alveoli of the lungs sufficiently.  相似文献   
72.
The planar Hajós calculus is the Hajós calculus with the restriction that all the graphs that appear in the construction (including a final graph) must be planar. We prove that the planar Hajós calculus is polynomially bounded iff the Hajós calculus is polynomially bounded.  相似文献   
73.
    
This article proposes a representation method of assembly tasks that enables a robotic system to carry out the tasks under uncertainty. The assembly task is represented by the sequence of contact states and control parameters that are generated by repeated measurements of force sensor outputs with the guide of control sphere conditions. The article describes how the control sphere conditions guarantee the correct transitions of contact states between objects along the sequence of the contact states. Finally the article demonstrates the effectiveness of our representation method by experimental works. © 1998 John Wiley & Sons, Inc.  相似文献   
74.
In order to deduce the burning characteristics of aluminum (Al) particle in solid propellant, a model experiment has been carried out with Al spheres of 3 mm ∼4 mm dia. in the oxidizing atmospheres at elevated pressures. As one of the investigation items, X-ray microanalysis for the burning-interrupted Al spheres was conducted along the straight lines crossing cap-like Al2O3 islands attached on unburned Al. It was clarified that, on the way of burning, in the case of Al sphere and plausibly on the burning surface of the particle also, there exist numerous Al2O3 islands, large and small, floating on molten Al sea; but even on the sea part, which seemed pure Al only, the surface is covered mostly with Al2O3 film. The similar analysis was applied to the Al foils ignited with Joule heating. It was witnessed, however, that contrary to the sphere surface there remains still neat Al in the vicinity of burning-interrupted surface. This fact may introduce low ignition temperature (933 K ∼ 963 K) and high deflagration velocity along the surface (for example. 2500 mm/s, with test piece of 0.11 mm thick, 5 mm wide; 8 MPaO2 ) with Al foils.  相似文献   
75.
A simple method to evaluate the adhesive force between solid oxidizer and polymeric fuel-binder is presented. As an illustration, hydroxyl-terminated polybutadiene (HTPB) sticks including several different bonding agents are bonded on ammonium perchlorate (AP) single crystals, and stress-strain history until rupture occurs is obtained by applying uniaxial tensile stress perpendicularly to the adhesion surface. Further, whether each bonding agent reacts with AP or not was analysed with pursuing infrared absorption spectra. The hypothesis that the interfacial adhesive force arises from hydrogen bonding force is proposed.  相似文献   
76.
Increased heat shock protein expression after stress in Japanese quail   总被引:1,自引:0,他引:1  
The health care received from first admission to a pediatric rheumatology clinic to 9-year follow-up was assessed in 109 patients with chronic inflammatory rheumatic diseases or chronic idiopathic musculoskeletal pain. Ninety-five of the patients had received hospital care after the first admission, of whom 53 patients > or = 18 years, 21 patients < 18 years, and 33 parents of patients < 18 years rated their degree of satisfaction with the health care from 0 to 10. Mean scores of satisfaction with different aspects of care ranged from 6.0 to 9.6. Among patients > or = 18 years, those with idiopathic pain were less satisfied than those with inflammatory rheumatic diseases on the availability of care (mean 6.4 vs. 8.5, p < 0.001), continuity of care (mean 6.5 vs. 8.4, p < 0.001), and empathy of the health care providers (mean 6.7 vs. 7.9, p <0.05). The diagnostic group and the occurrence of remission predicted the level of global satisfaction in patients > or = 18 years. In patients < 18 years, chronic family difficulties predicted patient satisfaction and physical disability and chronic family difficulties predicted parent satisfaction. In conclusion, most parents and patients with inflammatory rheumatic diseases were satisfied with the health care. However, some patients with idiopathic pain had unmet needs for care.  相似文献   
77.
A successful optical transmission experiment at 400 Mbit/s was carried out with two OEIC modules over 4 km with an optical power margin of 4 dB. The modules with monolithic LD/driver and PIN/amp ICs were fabricated by a new technique to realise compactness and stability.  相似文献   
78.
  总被引:1,自引:0,他引:1  
The online removable square packing problem is a two-dimen-sional version of the online removable Knapsack problem. For a sequence of squares with side length at most 1, we are requested to pack a subset of them into a unit square bin in an online fashion where the online player can decide whether to take the current square or not and which squares currently in the unit square to remove. The goal is to maximize the total packed area. Our results include: (i) No online algorithm can achieve a better competitive ratio than . (ii) The matching upper bound is achieved by a relatively simple online algorithm if repacking is allowed. (iii) Without repacking, we can achieve an upper bound of 3 by using the concept of bricks of Januszewski and Lassak. (iv) The offline version of the problem admits a PTAS. Research supported by NSFC (10231060).  相似文献   
79.
In our previous study, we found that trans-2-decenoic acid ethyl ester (DAEE), a derivative of a medium-chain fatty acid, elicits neurotrophin-like signals including the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in cultured mouse cortical neurons. Here, we examined the efficacy of intraperitoneal administration of DAEE on the treatment of a mouse model of the cerebral infarction caused by unilateral permanent middle cerebral artery occlusion (PMCAO). DAEE-treatment (100 μg/kg body weight injected at 0.5, 24, 48, 72 h after PMCAO) significantly restored the mice from PMCAO-induced neurological deficits including motor paralysis when evaluated 48, 72, and 96 h after the PMCAO. Furthermore, DAEE facilitated the phosphorylation of ERK1/2 on the infarction side of the brain when analyzed by Western immunoblot analysis, and it enhanced the number of phosphorylated ERK1/2-positive cells in the border areas between the infarction and non-infarction regions of the cerebral cortex, as estimated immunohistochemically. As the infarct volume remained unchanged after DAEE-treatment, it is more likely that DAEE improved the neurological condition through enhanced neuronal functions of the remaining neurons in the damaged areas rather than by maintaining neuronal survival. These results suggest that DAEE has a neuro-protective effect on cerebral infarction.  相似文献   
80.
This study was conducted to investigate the effects of sonicated bacterial extracts (SBEs) from anaerobic Gram-negative bacteria on periapical fibroblast obtained from the apical portion of human periodontal ligaments. Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum were chosen from among the endodontic bacteria isolated from root canals having a periapical lesion and compared in terms of their cytotoxicity. The purpose of this study was to examine which bacteria are involved in the development of periapical inflammation. The anaerobes were cultured under strict anaerobic conditions, and the bacterial cells were then harvested by centrifugation after incubation. The concentrated cell suspensions were sonicated and subsequently centrifuged. An SBE was made of each of the filtered supernatants. Each SBE was added to cultures of periapical fibroblasts. The cell growth and proliferation were measured by the MTT method after 3, 5, and 7 days. The SBEs from P. endodontalis, P. gingivalis, and F. nucleatum inhibited the growth of the fibroblasts, whereas the SBE from P. intermedia did not inhibit it. The SBEs from P. gingivalis and F. nucleatum inhibited the fibroblast growth more strongly than did the P. endodontalis, P. gingivalis, and F. nucleatum may participate in the development of periapical lesions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号